Liquid dispensing device



Patented July 11, 1944 UNITED STATES PATENT OFFICE LIQUID DISPEN SIN GDEVICE Paul E. Waugh, Fort Wayne,

Ind., assignor to Tokheim Oil Tank and Pump Company, Fort Wayne, Ind., acorporation of Indiana 20 Claims.

This invention relates to a process and apparatus for separating airand/or gases from liquid being dispensed and, more particularly, to aservice station pump for dispensing gasoline and other motor fuelwherein means is provided during the dispensing operation forcontinuously separating air and gases froml the gasoline or otherliquid.

Among the objects of the present invention are to provide a process andapparatus adapted for use in connection with the dispensing line of aliquid dispenser, including service station pumps adapted to dispensegasoline and other motor fuel, wherein the air and gas are separatedfrom the liquid as the latter is being dispensed and are ejected througha constantly open orice to atmosphere and wherein the airfree liquid isprevented from escaping or passing through said constantly open vent; toprovide an air separating means and method for liquid dispensing whereinthe separating means is provided with a constantly open orifice whereinmeans is provided for tending to eject or cause a mixture of uids topass therethrough and wherein additional means is provided forpreventing one type of fluid from passing through the separator orificewhile permitting another type of duid to pass freely therethrough; toprovide an air separator for a liquid dispenser such as a servicestation pump wherein gasoline flowing through the dispensing line,passes into a separating chamber to free the air and gas therefrom,wherein the air separation chamber has a constantly open orifice toatmosphere and wherein means is provided for creating a predeterminedpressure in said separation chamber tendingY to force air and liquidthrough the constantly open orifice and wherein additional means isprovided for centrifuging the liquid within said chamber in such amanner as to cause it to move away from the constantly open aperturewhereby to preclude the liquid passing therethrough while permitting thefree passage of air therethrough; to provide an air separator for aservice station pump having in combination with the usual iiuid forcepump adapted to force liquid into a separation chamber, which isprovided with a spring loaded valve adapted to open under apredetermined pressure an-d which separation chamber is provided with aconstantly open orifice and wherein means is provided associated withsaid orice comprising a second pump of greater eliciency with respect toliquid than the main dispensing pump when taken with its by-pass valvebut of therethrough; to provide a service station pump` which combines aliquid forcing, pump for forcing liquid through the dispensing line witha by-pass valve together with a spring loaded delivery valve associatedwith an air separationv chamber connected with the discharge side ofsaid pump and with the by-pass valve and spring loaded delivery valvewherein the air separation chamber has a constantly open vent toatmosphere for the discharge of separated air andv gas to atmosphere andwherein there is associated with this constantly open vent a secondpumping means having a greater eiciency for liquid than the rst pumpwhen taken with said valves butrof lower efficiency wit-hv respect toair or gas than the pressure within the air separator chamber asdetermined by the delivery or relief valve whereby to cause a sufficientcounter-active pressure to be exerted on the liquid in the separationchamber which tends to escape through the constantly open port so as toprevent the same from escaping while at the same time permitting thepassage of air therethrough; to provide an air separator disposed in thedispensing line of a service station pump in advance of the meter andthrough which liquid is adapted to ow during a dispensing operation,said` air separator chamber having means for separating the air and gasfrom the gasoline as it flows therethrough andv having means freely toeject the air or separated gas therefrom while precluding the escape ofliquid therefrom during dispensing without the use of liquid returnlines from the air separator back to the system; to provide such type ofair separator having, in combination with the air separator chamber andthe constantly open port to atmosphere, an expansion chamber adapted topermit the liquid in the air separator chamber and in the system toexpand during hot weather while idle and at the same time having meansfor causing sai-d expanded liquid automatically to be drawn back intothe separation chamber and passed through the liquid dispensing lineWithout permitting said liquid to escape toVv atmosphere along with theejection of separated air and/or gas to atmosphere; to provide an airseparator disposed in the dispensing line having a separation chamberprovided with a constantly open orifice and including associated meansduring dispensing for maintaining the liquid in the separation chamberunder pressure, while permitting air and gas to flow freely through aconstantly open aperture while preventing liquid from dischargingthrough said aperture and at the same time preventing access of outsideair to the liquid in the separation chamber whereby to cut down gasolineevaporation to the minimum; to provide an air separator disposed in thedispensing line of a service station pump having a constantly openorifice through which air and gases are free to be discharged togetherwith means for maintaining the separation chamber under pressure duringdispensing whereby to preclude evaporation of the more or less volatileliquid being dispensed; to provide an air separator for a gasoline pump,constructed and arranged to separate and discharge air and gas whilepreventing evaporation of gasoline through the air discharging orifice;to provide these and other objects of invention as will be apparent froma perusal of the following speciiication when taken in connection withthe drawing, wherein:

Figure 1 shows the conventional type of gasoline pump, parts of thehousing being broken away to show the location of the instant invention.

Figure 2 is a cross sectional view of the invention.

Figure 3 is a section taken on line 3 3 of Fig. 2 showing the passagesin the air separating device.

Referring now more particularly to the drawing:

The invention is shown in connection with a dispensing device of theservice station pump type, it being understood that in so far as thebroad aspects of the invention are concerned it may be utilized in anytype of dispensing device in which it is desirable to separate air orother gases and to discharge them free of the dispensed or owing liquid.Inasmuch as the invention is adaptable to the separation of air and gasfrom volatile motor fuel, I have disclosed the invention in connectionwith a service station pump of the conventional type.

The pump is shown as having a housing 4 which encloses the variouselements making up a service station pump assembly including the air fseparator 5, the meter 6 and the sight gauge l. The meter, which may beof any conventional type, is shown as driving the conventional type ofcomputer 8. The suction pipe 9 forming a portion of the dispensing lineconnects the pump proper of the separator 5 to a foot valve I3 locatedin the bottom of the reservoir or tank II containing the gasoline orother liquid to be dispensed. A pipe I2 likewise forming a part of thedispensing line directs the liquid from Ithe air separator chamber tothe meter 6. From the meter 6 the liquid or gasoline flows by the pipeI3 through the dispensing line I4 to the conventional type of hose I5which likewise forms a part of the dispensing line and which hose isshown as provided at its outer end with a nozzle I6 having the usualtype of manual control valve. An electric motor II is shown mounted onthe side of the air separating device. This motor not only drives thepump but is also utilized to drive an actuatable element of the airseparator by means of a, belt I8.

Referring particularly to Fig. 2, the suction pipe of the dispensingline is shown connected to a suction port I9 of the pump 28. This pumppreferably may be any type of positive displacement pump or may be acentrifugal pump. In the present embodiment the pump is provided with aby-pass valve 2I which is well known in the art and is shown enclosing apassage between the chamber 22 and a suction chamber I9. In the presentinstance, the air separating device and the pump mechanism are includedin a single unit or assembly but may be otherwise formed. The pump 20discharges into a portion 23 of the chamber 22 which is formed by a baleor separating partition or plate 24. The displacement pump 20 is shownsecurely attached to the lower end of the drive shaft 25 which shaftextends upwardly through the packing gland 26 of the separation chamber22 and continues upwardly through another packing gland 21 of theexpansion chamber 28. The expansion chamber 28 is vented Ito atmosphereby a small or restricted tube 29 which is constantly open to atmospherethrough the side of the housing 4. Between the two stuffing boxes 26 and21 means is provided in the shape of a pulley 30 securely attached bymeans of a key 3I to the shaft 25 for rotating the pump shaft. Near thebottom of the separation chamber 22 a, liquid outlet or outer flow portis provided which is normally closed by means of a delivery valve 32.The valve 32 is provided with a spring of sufficient strength to cause adefinite, substantial pressure to exist in the separation chamber 22before any liquid can pass through the outlet port I2 of the dispensingline.

Means is provided for connecting the separation chamber 22 with theexpansion chamber 28 by means of a constantly open, relatively largeorice or channel through which the separated air, vapors and other gasesmay freely pass during the dispensing operation or prior thereto andthrough which the liquid in the separation chamber and in flow line maypass or expand during hot weather while the pump is standing idle. Inaddition, means is provided in association with the chamber 22 and withthe constantly open orice connecting the chamber 22 with the expansionchamber 28 which, while permitting the free passage of air and gastherethrough, serves to prevent during dispensing operation the passageof liquid therethrough and into the expansion chamber 28. In short,means is provided for precluding the passage of liquid therethrough andthis is accomplished by exerting a pumping action tending to cause anyliquid which might otherwise be forced through this constantly openpassage due to the pressure in the dispensing line, Ito flow downwardlyor backwardly into the chamber 22. In the type of means which I haveutilized for exemplication of such a means, I provide in the chamber 22a centrifugal impeller 33 securely attached by means of a key 34 to adriving shaft 25. This driving shaft has a centrally located bore 35which extends from the upper end downwardly through the center of theshaft to a point level with the impeller or slightly therebelovv. Thisimpeller 33 is of the closed type and in the shaft several holes 36 aredrilled to allow communication between the bore 35 and the inner spaceof the impeller 33. The impeller is better shown in Fig. 3. It has asui-table number of vanes 31 shaped according to the art of centrifugalpumps and arranged in a direction in relation to the rotation of theimpeller to cause liquid or gasoline to be thrown outwardly from theimpeller. As shown in Fig. 3, the arrow indicates a counterclockwiserotation and the vanes 31 are shaped to suit such rotation. About theimpeller 33 a perforated cup-shaped baille is attached to the separatorbody by means of screws 40, which baille prevents agitation of theentire vessel of liquid but which allows free flow or communicationbetween the impeller chamber and the separation chamber.

The entire air separating device, that is, the pump, air separator andthe expansion chamber, is rigidly attached to the pump frame member 4|by means of cap screws 42.

Operation In the operation of the present device, when the motor switchwhich is generally associated with the nozzle support as shown in theupper right hand portion of Fig. l is closed it causes the motor l1 tostar-t which, in turn, rotates the pump shaft 25 by means of a belt I8.This will immediately operate the displacement pump 20, to suck gasolinefrom the underground reservoir and force it through the dispensing lineI2. The gasoline is discharged from the pump 2|) into the separationchamber 22 through the port 23. associated with the pump are designed toopen at different pressures. Delivery valve 32 has a spring which causesit to open at a pressure of approximately 20 pounds, while the valve 2|,which is the pump by-pass valve, is adapted to open at a pressure ofapproximately 22 pounds. When the valve in the hose nozzle I3 is closedor when the delivery valve, if one is used, is closed, then no liquidwill pass valve 32 and pressure will be created in the chamber 22 untilit reaches 22 pounds which causes the by-pass valve 2| to open. Theopening of this valve allows the liquid to bypass through the pump as iswell known in the art. When the shaft 25 is rotated, both the pump 2Uand the centrifugal impeller 33 are rotated together. The impeller 33 isso designed as to attempt, if liquid were present in the chamber 28, todraw the same into the separation chamber 22. However, in normaloperation no liquid will be present in the expansion chamber 28. Becauseof the fact that the centrifugal impeller cannot build up sufficient airpressure, there is no forced delivery of airY from the chamber 28 intothe separation chamber 22. However, if, from a leaky suction line orfrom the vapor and gasoline forming from the pumping of volatile liquid,if entrained air or gas should be drawn in with the gasoline through thepump 2|) into the chamber 22, this air will rise to the top of thechamber because of the difference of specific gravities. The impeller 33is made of suitable diameter as compared to its speed of rotation so asto be capable of producing a higher liquid pressure than the valve 2|will allow. Due to this fact, the pressure formed and governed by thepump 20 and the valve 2| will never equal the possible liquidefl'iciency of the impeller 33. Therefore, no liquid will ever pass orbe forced through the impeller passages 35 and 36 into the expansionchamber 28, during operation of the' device.

Hence it will be seen that by reason of the constantly open vent and theassociated impeller mechanism any air which may be delivered to theseparation chamber 22 will be vented freely to atmosphere, but at thesame time no liquid will be allowed to pass due to the centrifugalaction of the impeller vanes. When the attendant opens the nozzle valveI6 the gasoline will vpass through the valve 32, flow through the flowline I2 to the The valves 2| and 32 in the air separator a meter 6 whereit is measured and recorded by the computer 8. The measured liquidleaves the meter 6 by the line I3 and flows through the sight gauge 1and the pipe I4 to the hose |5 and to the nozzle I6.

Under some conditions during idleness of the pump the liquid may expandin the dispensing line into the expansion chamber 28. Such occasionwould be when the dispensing operation has drawn cold contracted liquidfrom the underground tank into the dispensing system so that on a warmday when the liquid is exposed to atmospheric temperature it will thenexpand and the pump having been idle the increased volume of liquid willbe forced through the impeller 33 to the passages 35 and 36 into theexpansion chamber 28. The expansion chamber may be of any suitable sizeto accommodate the maximum expansion in any climate. In the dispensingoperation, upon opening the nozzle valve the liquid will flow from theseparation chamber 22 and, because of the greater liquid efficiency ofthe centrifugal impeller 33, the expanded liquid will be drawn from theexpansion chamber 28 through the passages 35 and 36 into the chamber 22so that chamber 28 will be drained before the pump 28 can deliver anymore gasoline to the discharge line. As soon as all of the surplusliquid is delivered by the impeller 33 and only air is present, nofurther delivery of air or liquid will occur by this impeller.

From the foregoing it will be seen that the present air separatorrequires but few parts, requires no introduction of a return from theexpansion chamber to the suction side of the pump or to the undergroundtank and requires no floats, check valves or other devices as now usedin the art. The invention is not restricted to the type of pump 20 shownas this pump could equally well be a centrifugal pump or it could be anytype of vane or rotary pump. If a pump should be employed for the pump20 which, because of mechanical advantages, would be run at a slowerrate of speed than suitable for the impeller 33, reduction gearing ofany type could be introduced between the two pumps to allow the impeller33 to travel at a higher speed than the delivery pump 20. The pumpscould be driven by two separate motors or by two separate shafts havingdifferent sized gearing from the same motor. However, the illustratedform is the preferred one where only one belt is required and theimpeller 33 could be made of suitable design to compensate for itsslower speed of rotation.

It will thus be seen that when the main pump is operating to create apressure in the separation chamber, the by-pass valve and the action ofthe pump determines the maximum pressure therein which tends to forcethe liquid and the air out through the opening. It will also beappreciated that the action of the second pump, in the present instance,the centrifugal impeller, is such that this latter pump is moreeflicient with respect to liquid than the main dispensing pump whentaken with its by-pass valve but has a lower efficiency with respect togas or air than the pressure within the air separator chamber asdetermined by the relief valve by which condition one type of fluid,to-wit, air and/or gas is permitted to pass freely to atmosphere, andanother type of liquid, to-wit, gasoline or motor fuel being dispensed,is prevented from being passed through the constantly open vent toatmosphere. Thus it will be seen that my present invention is admirablein al1 respects as an air separator in a liquid dispensing device,particularly for a gasoline service station pump, since it eliminatesthe necessity of providing a liquid return line from the air separatorback to the suction side of the pump or back to the underground tank orback to any part of the system. It will also be seen that by placing thecentrifugal impeller directly within the separation chamber, the actionis to centrifuge the liquid away from the constantly open atmospherewith a greater force than the pressure within the separation chamber,tending to force this liquid outwardly through the constantly open ventwhereby the lower end of the constantly open vent is connected to theseparated air and/ or gas within the upper portion of the separationchamber which may pass freely therethrough to atmosphere without dangerof any liquid escaping. It will also be appreciated that by reason ofthe expansion chamber at the upper end of the constantly open vent, whenthe pump is idle and if, for any reason, an expansion of the liquid inthe dispensing line takes place, this expansion will automatically betaken care of by the expansion chamber and upon subsequent resumption ofthe dispensing operation the first action of the pumping means in theseparation chamber is to suck this expansion liquid from the expansionchamber downwardly into the separation chamber and cause it to be passedthrough the dispensing line while at the same time permitting the freepassage of air and/or gas through the constantly open vent.

It will also be appreciated that by reason of my construction the airseparator keeps the liquid in the separation chamber 22 under pressureas distinguished from the conventional type of air separator heretoforeused, which allows liquid together with some air to pass from thecompression or separation chamber to a float or atmospheric pressurechamber. In prior devices, in handling a volatile fluid such as gasolinethe gasoline in this float or atmospheric pressure chamber is thus morereadily exposed to atmospheric pressure and consequently a quickerevaporation occurs than if the liquid be confined under pressure as itis in chamber 22 of the present invention. My present type of airseparator tends to prevent evaporation by maintaining chamber 22 underpressure and in addition, due to this pressure, atmospheric air isprecluded from entering the chamber during dispensing. At the same time,liquid is precluded from being discharged through the opening 35 and airand/or gas rn ay freely pass therethrough.

With regard to the orifice or passage 35, this passage may be of anysize. As a matter of fact, the larger, the better up to a certain point,for it is the centrifugal action of the impeller that performs thefunction of preventing liquid from discharging therethrough, whilepermitting the air freely to escape therethrough, and therefore thelarger the passage through the shaft, the more efciently the device willoperate to drain the expansion chamber 28 of liquid due to expansionduring idleness.

What I claim is:

l. In dispensing line of a liquid dispenser, means connected in seriesin said line forming a liquid and gas separation chamber, means forpumping liquid to be dispensed through said line and into said chamber,said separation chamber having a constantly open orifice to atmosphere,whereby the pressure of said pumping means tends to force liquid beingdispensed and gas therein through said orice, centrifugal pumping meansdisposed in said separation chamber and associated with said orifice andadapted to centrifuge the liquid tending to pass outwardly through saidorifice, away from said orifice while permitting the free passage of gastherethrough.

2. In combination with the dispensing line of a service station pump, afirst pumping means for creating a flow through said dispensing line, agas separator chamber connected in series in said line on the dischargeside of said pump, a spring loaded by-pass for said pump, a constantlyopen vent for said separation chamber, and additional pumping meansassociated with said constantly open vent and exerting a force on theliquid in said chamber in excess of the pressure of said spring of theby-pass preventing passage of liquid in said chamber through saidoriiice during dispensing.

3. In combination with a dispensing line of a service station pump, aiirst pump for creating a flow through said dispensing line, a gasseparator chamber associated with the discharge side of said pump, aspring loaded by-pass for said pump adapted to receive liquid from theseparation chamber and to return liquid back to said pump, a liquidoutlet for said separation chamber, a spring loaded valve for saidliquid outlet adapted to open at a lower liquid pressure in said chamberthan the pressure at which said spring loaded by-pass opens, aconstantly open vent for said separation chamber, and a centrifugal pumpdisposed in said separation chamber and associated with the constantlyopen vent, said centrifugal pump being constructed and arranged tocentrifuge the liquid away from said vent with a force greater than theforce of the spring of said by-pass while permitting the free passage ofgas through said vent.

4. An air separator for a liquid dispensing system in combination withmeans forming a separation compartment, a liquid inlet to saidcompartment, pumping means for forcing liquid through said liquid inlet,a liquid outlet for said compartment, said pumping means having a springloaded by-pass Valve adapted to open at a predetermined pressure, saidseparation compartment having therein a shaft having an associatedconstantly open vent connecting the interior of said separationcompartment with atmosphere, said vent having associated therewith acentrifugal impeller on said shaft, and means to actuate said shaft andimpeller to centrifuge liquid in said chamber away from said vent duringdispensing with a force greater than the pressure at which said by-passvalve opens whereby to preclude passage of liquid to atmosphere duringdispensing while freely discharging air through said vent to atmosphere.

5. An air separator for a liquid dispenser comprising a casing, saidcasing having a partition forming an inlet chamber adapted to beconnected to the inlet side of a dispensing line, a pump in said casinghaving its inlet connected to said inlet chamber and its outletconnected to a main chamber in said casing, said inlet chamber having aspring loaded by-pass valve connecting the inlet of said pump with themain chamber within said casing, said casing having an outlet, said pumphaving an upstanding shaft passing upwardly through said casing, theupper portion of said shaft having an axial bore opening through the topof said casing, a centrifugal impeller concentrically mounted upon saidshaft about the bottom portion of said axial bore, and means for drivingsaid shaft to rotate said pump and said centrifugal impeller tocentrifuge the liquid in said chamber with a force greater than theforce of the spring of said by-pass valve.

6. An air separator for a liquid dispenser comprising a casing, saidcasing having a partition forming an inlet chamber adapted to beconnected to the inlet side of a dispensing line, a pump in said casinghaving its inlet connected to said inlet chamber and its outletconnected to a main chamber in said casing, said inlet chamber having aspring loaded by-pass valve connecting the inlet of said pump with themain chamber within said casing, said casing having a liquid outlet,said pump having an upstanding shaft passing upwardly through saidcasing, the upper portion of said shaft having an axial bore openingthrough the top of saidcasing, a centrifugal impeller concentricallymounted upon vsaid shaft about the bottom portion of said axial bore,means for driving said shaft to rotate said pump and said centrifugalimpeller, said impeller centrifuging the liquid in said chamber awayfrom said bore with a force greater than the force of the spring of theby-pass valve, and an expansion chamber having a constantly openconnection to the upper end of the bore of said vertical shait, saidexpansion chamber having a constantly open connection to atmosphere.

'7. In a service station dispenser, the combination with means forming adispensing line having its end adapted to be connected to a Asource ofliquid supply, a pump, said line being adapted to be connected to theinlet of said pump, a lmeter connected to the pump discharge, and thedischarge of said meter having a portion of the dispensing lineconnected thereto, means for controlling the dispensing of liquidthrough said line, means for driving said pump, a gas separation chamberdisposed in said line between the pump and the meter, said gasseparation chamber havn ing a constantly open conduit connected toatmosphere, and pressure means acting on the liquid in said chamber forpreventing the discharge of liquid through said constantly open conduitduring dispensing while permitting the discharge of gas therethrough.

8. In a liquid dispensing device, in combination with means formingdispensing line, a liquid displacement meter in said line, airseparating means in said line in advance of the meter including achamber having a constantly open oriiice open to air and into whichchamber the liquid to be dispensed is adapted to flow, means actuatableduring a dispensing operation for maintaining said chamber constantlyunder pressure whereby causing the discharge of airin said chamberfreely through said orifice, and means precluding Ythe discharge ofliquid in said chamber through said open oriiice during dispensing.

9. In a liquid dispensing device, the combination of means forming adispensing line, a meter in said line, means for controlling the ow ofliquid through said line, air separator means in said line in advance ofthe meter, said separating means including a chamber disposed in seriesin said line, said chamber having a constantly open passage, anexpansion chamber connected to said passage, said expansion chamberhaving a constantly open connection to atmosphere, means actuatableduring dispensing for maintaining said first-mentioned chamber underpressure, for discharging air freely through said passage. and means forpreventing discharge of liquid through said passage during maintenanceof pressure in said chamber, and means for-.rendering said last namedmeans inoperative whereby to permit a restricted ilow of liquid fromsaid first-mentioned chamber into said expansion chamber upontermination of dispensing to accommodate expansion of liquid in thedispensing line due to rise in temperature.

10. In a service station dispenser, the combination of a dispensing lineincluding pumping means for forcing liquid under substantial pressurethrough said line, an air separating chamber connected in series in saidline on the discharge side of the pump and through which chamber liquidisadapted to pass under substantial pressure during the operation of thepumping means, said chamber having a constantly open vent to atmospherewhereby the uid pressure in said chamber is adapted freely to ejectaccumulated air directly to atmosphere, and means in saio1 chamberdirectly engageable with the liquid body under pressure therein forcausing a greater pressure than that existing in said chamber to beexerted on said liquid at said open vent and in a direction away fromsaid vent whereby to prevent the discharge of liquid in said chamberthrough said vent.

11. A gas separating mechanism for a fluid dispenser comprising achamber having a liquid inlet and a liquid outlet, said chamber beingadapted to be connected to a flow line whereby liquid being passedthrough the ilow line is adapted to low through said chamber during adispensing operation, said chamber so disposed in said dispensing lineincluding an open vent whereby the liquid in said chamber and alsoaccumulated gas therein tend to discharge through said open ventthereof, and means directly engaging and exerting a force on the liquidbody in said chamber in a direction for preventing the liquid frompassing through said vent during dispensing flow While permitting thegas in said chamber to pass freely through said Vent.

l2. In a dispensing line of a liquid dispenser through which liquid isadapted to flow under pressure, means connected in series in said lineforming a liquid and gas separation chamber through which the liquidbeing dispensed flows, said separation chamber having a constantly openorifice to atmosphere, means for producing a fixed predeterminedpressure on the liquid within the chamber tending to force the liquidbeing dispensed and gas therein through said orice, and means operativeduring dispensing for exerting a greater force on said liquid in saidchamber in a direction away from said orifice preventing the passage ofliquid therethrough during dispensing while permitting the free passageof gas therethrough.

13. In a liquid dispensing system, in combination with means forming adispensing line through which liquid is adapted to ilow under pressure,an expansion chamber, an air separator disposed in said line, includinga constantly open vent connection with said expansion chamber, saidexpansion chamber being unrestrictedly open to atmosphere, and said ventconnection forming the sole connection between the expansion charnberand the system, and means associated with said constantly open ventexerting a force on the liquid in said chamber for preventing passage ofliquid through said vent during dispensing operation while permittingthe free passage of air therethrough to said expansion chamber duringdispensing.

14. In a service station dispenser, the combination of a dispensing linehaving its end adapted to be connected to a source of liquid supply, apump, said line adapted to be connected to the inlet of said pump, aliquid displacement meter, the discharge line from said pump having aconnection to said meter, and the discharge of said meter having aportion of the dispensing line connected thereto, means for controllingthe dispensing of liquid through said line, means for driving said pump,and an air separation chamber disposed in said line between the pump andthe meter, a by-pass for said pump adapted to open at a predeterminedpressure, said air separation chamber having a constantly open portconnected to atmosphere, and means associated with said constantly openport and acting on the liquid in the separator with a force greater thanthe pressure at which said by-pass opens for permitting the free passageof air through said constantly open port while preventing the passage ofliquid therethrough during dispensing.

15. In a dispensing apparatus, in combination with means forming adispensing line through which liquid is adapted to be forced underpressure during the dispensing operation, means for controlling the flowof dispensed liquid through said line, a meter in said line, means insaid line in advance of the meter comprising an air separator chamberhaving a constantly open vent, a plurality of pumps and means foractuating the same, one of said pumps being a positive displacement pumpand being disposed to tend to force liquid and air through saidconstantly open vent in said air separation chamber and the other ofsaid pumps being a centrifugal pump and serving to prevent the passageof liquid in said chamber through said constantly open vent duringdispensing while permitting the free passage of air therethrough.

16. A liquid dispensing apparatus comprising a source of liquid supply,a dispensing line connected to said source of supply, a pump forpropelling liquid from the supply source through said dispensing line, agas separator arranged in the dispensing line and adapted to separateentrained gas from the liquid, a gas discharge port leading from theseparator through which separated gases are discharged, means associatedwith said port for preventing the escape of liquid therethrough, andmeans controlling said last mentioned means to operate said means onlyduring operation of said pump.

1'7. A liquid dispensing apparatus as defined in claim 16 wherein saidliquid escape preventing means associated with the port constitutes animpeller, and wherein the impeller and the pump are driven from a commonpower source.

18. In a dispensing line of a liquid dispenser, means in said lineforming a liquid and gas separation chamber, pumping means for causingliquid to flow under pressure through said line and into said chamber,said chamber having a constantly open orifice to atmosphere, thepressure of liquid in said chamber tending to force the liquid beingdispensed and gas therein outwardly through said orifice, and secondpumping means arranged to propel fluid in a reverse direction throughsaid orifice and exerting a greater pressure on the liquid than thepressure within said chamber for preventing liquid from passing throughsaid constantly open orice during dispensing while permitting the freepassage of gas through said orifice.

19. A liquid dispensing apparatus comprising a dispensing line adaptedto be connected to a source of supply, a chamber disposed in said line,said chamber having an opening to atmosphere through which air andliquid vapor' are adapted to pass, a positive displacement pump adaptedto propel liquid, liquid vapor and air through said line, a centrifugalpump disposed on the outlet side of said positive displacement pump andadapted to receive liquid, liquid vapor and air therefrom, saidcentrifugal pump being operatively associated with said chamber opening,and a dispensing outlet, said centrifugal pump being adapted to effect aseparation of liquid from the liquid vapor and air, whereby the liquidis delivered to said dispensing outlet and the liquid vapor and air arepassed through said chamber opening, and common driving means beingprovided for both the positive displacement pump and the centrifugalpump whereby a predetermined speed ratio between said pumps ismaintained.

20. A liquid dispensing apparatus comprising a dispensing line adaptedto be connected to a source of supply, a chamber disposed in said line,said chamber having an opening to atmosphere through which air andliquid vapor are adapted to pass, a positive displacement pump adaptedto propel liquid, liquid vapor and air through said line, a centrifugalpump disposed on the outlet side of said positive displacement pump andadapted to receive liquid, liquid vapor and air therefrom, saidcentrifugal pump being operatively associated with said chamber opening,and a dispensing outlet, said centrifugal pump being adapted to effect aseparation of liquid from the liquid vapor and air, whereby the liquidis delivered to said dispensing outlet and the liquid vapor and air arepassed through said chamber opening, a pressure controlled by-pass valvearranged in association with the positive displacement pump, in returnby-pass relation thereto, and wherein a pressure controlled deliveryvalve is associated with the dispensing outlet, the operating pressureof said delivery valve being lower than the operating pressure of theby-pass valve, and the pressure force of said centrifugal pump on theliquid being greater than the operating pressure of the by-pass valve.

PAUL E. WAUGH.

